Underfloor LPG tank regulations

guerdeval

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is anyone aware of regulations regarding underfloor LPG tanks?, van passed MOY yesterday and we noticed the red painted tank had a rust issue, we didn’t poke it just in case but the van is just 10 years old so is the tank, I’ll get the tank replaced but can I hope to use the same fittings etc …
 
Hi ya,
So have you noticed a leak on the Gas side of things ?.
I think (Not being a gas engineer) that if tested at all it might just be a visual inspection & Pressure test !.

I think that most external under slung tanks will suffer Weather or Damage over the years. So if you’re not happy then replace is a fair option & will give you piece of mind.
 
If you shotblast and paint with zink rich epoxy primer the new tank wont rust for 20 years, finish withpoly 2 pack or cloranated rubber

(QUOTE) it is, recommended by gassit that the tank is painted annually with stone chip to prevent stone chips and rust .
 
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If you shotblast and paint with zink rich epoxy primer the new tank wont rust for 20 years, finish withpoly 2 pack or cloranated rubber.
Gas tanks rust internally Trev, and it’s important to replace gas tanks as per manufacturer’s recommendations, and safety regulations which apply. But when you consider the consequences of a tank leaking, or rupturing I would always air on the side of safety. Bulk storage tanks supplying homes or buildings can last up to 30 years, but require testing after 15 years, and every three years thereafter.
But I would have thought a vehicle tank such as installed in a Moho would last 10-15 years. But I would replace one after 10 years and sleep well.
 
Gas tanks rust internally Trev, and it’s important to replace gas tanks as per manufacturer’s recommendations, and safety regulations which apply. But when you consider the consequences of a tank leaking, or rupturing I would always air on the side of safety. Bulk storage tanks supplying homes or buildings can last up to 30 years, but require testing after 15 years, and every three years thereafter.
But I would have thought a vehicle tank such as installed in a Moho would last 10-15 years. But I would replace one after 10 years and sleep well.
Yes prob correct, i used to see big tanks pre tested in the serocco works in belfast, we used to shotblast the cone end edges for them to get a clean weld.
 
is anyone aware of regulations regarding underfloor LPG tanks?, van passed MOY yesterday and we noticed the red painted tank had a rust issue, we didn’t poke it just in case but the van is just 10 years old so is the tank, I’ll get the tank replaced but can I hope to use the same fittings etc …
you know, If I saw something that looked like it could be a problem on a pressured gas tank, I would for sure poke it just in case before I put any gas in it!
 
you know, If I saw something that looked like it could be a problem on a pressured gas tank, I would for sure poke it just in case before I put any gas in it!
With the tank under pressure I would doubt if poking it would penetrate the tank.
If the erosion was that serious, under pressure the tank would have ruptured.

But what must be taken into consideration is what’s happening within the tank.
The fact that the liquid is moving around within the tank when the van is being driven normally leads to additional internal erosion.
 
Interestingly today on motorhomer, a well respected member with a background in gas and installations stated that gas bottles do not rust from the inside.
I am not trying to start a 'fight', but it would be interesting to know which viewpoint is correct.

Davy
 
Interestingly today on motorhomer, a well respected member with a background in gas and installations stated that gas bottles do not rust from the inside.
I am not trying to start a 'fight', but it would be interesting to know which viewpoint is correct.

Davy
Rust is caused by oxidation. There's not much oxygen present inside a gas bottle! I suspect that they do not corrode internally.
 
Interestingly today on motorhomer, a well respected member with a background in gas and installations stated that gas bottles do not rust from the inside.
I am not trying to start a 'fight', but it would be interesting to know which viewpoint is correct.

Davy
Well you get oily residue inside the tanks, I would think that stops rust but I don't know. I should know but I forget lol
 
The tank itself is not part of the MOT test but the fittings are, my van failed because of rusty straps and to be honest I was surprised when I saw the plastic covered straps that were supplied with the tank were completely rusted through with only the plastic holding anything, luckily for me when I installed the tank on the van I lifted it into position using straps which I never removed.
 
I fitted a new tank about a year ago but before I did I gave it two coats of zinc primer then two coats of white underseal + one coat of red paint + I have a huge alloy shield in front of it to protect it from stone chips.Ive put rubber inserts between the tank and the straps.
 

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I fitted a new tank about a year ago but before I did I gave it two coats of zinc primer then two coats of white underseal + one coat of red paint + I have a huge alloy shield in front of it to protect it from stone chips.Ive put rubber inserts between the tank and the straps.
Did you shotblast it first and then use 2 pack zink, not the cr-p you buy from motor stores.
 
I am the ex-gas engineer wot said I don't think they rust from the inside, because LPG contains a small amount of oil. I think the following, but I have never cut a tank open:
Oxygen causes steel to rust.
When it is manufactured obviously there will be air, with oxygen inside it.
Then it is filled to 80% full volume-wise with liquid petroleum gas.
The petroleum is refined from underground oil.
The liquid gas contains a small percentage of oil, because LPG is liquid petroleum gas.
This is different to LNG which is Liquid Natural Gas, i.e natural gas that has been compressed to a liquid state. The same stuff that your central heating boiler uses, and that doesn't contain any oil.
There will never be any oxygen inside a tank after it has been filled once and emptied. As it is emptied, the space is not taken up with air, it will always have the pressurised gas above the liquid gas.
Therefore there will never again be any oxygenated air inside the tank.
Some small droplets, or particles of oil will remain inside the tank, and my theory is that combined with the lack of oxygen, the tank won't rust inside.

I know some of the above to be true, some may not be and I stand to be corrected by anyone who has cut a healthy tank open.

Also when I last had a hab check done I asked the chap about the life of a tank and he said the legal requirement is to have a fixed tank inspected and certified every ten years. He said this is too expensive on a motorhome tank so it is cheaper to remove it and fit a new one. If the tank is found to be older than ten years it should not pass the habitation check.

As for straps going rusty inside the plastic coating, I recently got a bigger fresh water tank from CAK tanks. They supplied a set of stainless steel straps inside the plastic coating, and I can't see that deteriorating.
 
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